Sentinel3A

Sentinel-3A is the first satellite in the Sentinel-3 mission of the European Copernicus program. It is an Earth observation spacecraft operated by the European Space Agency (ESA) with data distributed through the EUMETSAT system for use by the Copernicus user community. The mission collects high-precision measurements of the oceans, land, and atmosphere to support weather forecasting, climate monitoring, maritime safety, and environmental surveillance.

The payload consists of four main instruments. The Ocean and Land Colour Instrument (OLCI) provides ocean color and land reflectance data across multiple spectral bands. The Sea and Land Surface Temperature Radiometer (SLSTR) measures surface temperatures on land and in the oceans. The Synthetic Aperture Radar Altimeter (SRAL) supplies radar altimetry data to determine sea surface height, wave height, and wind speed over the ocean. A Microwave Radiometer (MWR) supports atmospheric corrections by measuring water vapor along the signal path. Together, these instruments enable routine observations of sea surface temperature, sea surface height, ocean color, and land surface temperature.

Sentinel-3A was launched on February 16, 2016 from the Plesetsk Cosmodrome in Russia aboard a Rokot launch vehicle. It operates in a sun-synchronous near-polar orbit at an altitude of roughly 814 kilometers, with a repeat pattern designed to maximize global coverage. In combination with its twin, Sentinel-3B, the mission provides frequent, near-global coverage that supports continuous monitoring of marine and land environments and contributes to long-term climate records.